[PATCH v3 0/6] drm/v3d: Improve v3d_stats lifetime and locking

[Maíra Canal <mcanal@igalia.com>]

This series aims to improve the `struct v3d_stats` lifetime management.
The commit fa6a20c87470 ("drm/v3d: Address race-condition between per-fd
GPU stats and fd release") addressed a race-condition between the per-fd
GPU stats and the fd release by clearing `job->file_priv` before the V3D
per-fd structure is freed and assuring that `job->file_priv` exists
during the per-fd GPU stats updates.

However, this approach introduced a tricky file_priv NULL-ing dance with
the `queue_lock` spinlock. This series aims to address this issue in a
simpler way: converting `v3d_stats` from embedded structs to
heap-allocated, refcounted objects. This simplifies the code and leaves
`queue_lock` exclusively for job management.

The series also switches to raw seqcount helpers to resolve a lockdep
annotation issue, fixes missing error handling in drm_sched_entity_init(),
and removes the now-unnecessary dedicated fence_lock.

Best regards,
- Maíra

---
v1 -> v2:

- [All patches] Added Iago's R-b (Iago Toral)
- [3/6] s/kzalloc/kzalloc_obj
- [5/6] Add a comment explaining while the mutex is used in
        DRM_V3D_PARAM_CONTEXT_RESET_COUNTER (Iago Toral)
- Link to v1: https://lore.kernel.org/r/20260217-v3d-reset-locking-improv-v1-0-0db848016869@igalia.com

v2 -> v3:

- [5/6] Remove mutex from DRM_V3D_PARAM_CONTEXT_RESET_COUNTER (Tvrtko Ursulin)
- Link to v2: https://lore.kernel.org/r/20260305-v3d-reset-locking-improv-v2-0-fd53c91f7726@igalia.com

---
Maíra Canal (2):
      drm/v3d: Handle error from drm_sched_entity_init()
      drm/v3d: Remove dedicated fence_lock

Tvrtko Ursulin (4):
      drm/v3d: Use raw seqcount helpers instead of fighting with lockdep
      drm/v3d: Refcount v3d_stats
      drm/v3d: Hold v3d_stats references in each job
      drm/v3d: Attach per-fd reset counters to v3d_stats

 drivers/gpu/drm/v3d/v3d_drv.c    |  55 ++++++++--------
 drivers/gpu/drm/v3d/v3d_drv.h    |  46 +++++++++-----
 drivers/gpu/drm/v3d/v3d_fence.c  |   2 +-
 drivers/gpu/drm/v3d/v3d_gem.c    |  43 ++++++++-----
 drivers/gpu/drm/v3d/v3d_irq.c    |   2 +-
 drivers/gpu/drm/v3d/v3d_sched.c  | 133 +++++++++++++++------------------------
 drivers/gpu/drm/v3d/v3d_submit.c |   6 ++
 drivers/gpu/drm/v3d/v3d_sysfs.c  |   2 +-
 8 files changed, 147 insertions(+), 142 deletions(-)
---
base-commit: e597a809a2b97e927060ba182f58eb3e6101bc70
change-id: 20260215-v3d-reset-locking-improv-ffe16c35569b